Fire-through Ag contact formation for crystalline Si solar cells using single-step inkjet printing

• Published in: Journal of nanoscience and nanotechnology Vol. 12; no. 4; p. 3620
• Main Authors: Kim, Hyun-Gang, Cho, Sung-Bin, Chung, Bo-Mook, Huh, Joo-Youl, Yoon, Sam S
• Format: Journal Article
• Language: English
• Published: United States 01.04.2012
• ISSN: 1533-4880
• DOI: 10.1166/jnn.2012.5574

Inkjet-printed Ag metallization is a promising method of forming front-side contacts on Si solar cells due to its non-contact printing nature and fine grid resolution. However, conventional Ag inks are unable to punch through the SiN(x) anti-reflection coating (ARC) layer on emitter Si surfaces. In this study, a novel formulation of Ag ink is examined for the formation of fire-through contacts on a SiN(x)-coated Si substrate using the single-step printing of Ag ink, followed by rapid thermal annealing at 800 degrees C. In order to formulate Ag inks with fire-through contact formation capabilities, a liquid etching agent was first formulated by dissolving metal nitrates in an organic solvent and then mixing the resulting solution with a commercial Ag nanoparticle ink at various volume ratios. During the firing process, the dissolved metal nitrates decomposed into metal oxides and acted in a similar manner to the glass frit contained in Ag pastes for screen-printed Ag metallization. The newly formulated ink with a 1 wt% loading ratio of metal oxides to Ag formed finely distributed Ag crystallites on the Si substrate after firing at 800 degrees C for 1 min.